In the processing of sets or jobs fed from a copying or printing machine for stacking or post processing, it is a common procedure in the case of machines which feed the sheets from a printer or copier with the printed side of the sheet facing upwardly, to employ an inverter, so that as the sheets are fed from the printer or copier to the stacking or post processing machines the sheets are stacked in the correct order, printed side down.
The use of a sheet inverter between the stacker or the post processing machine causes a delay in the continuous feeding of the sheets so that inversion of sheets in a sheet inverter limits the upper range of the speed of the sheet delivery without causing a delay in the operation of the sheet printing or copying machine output. On the other hand, inversion of the sheets being fed face up makes necessary the inversion in order to properly stack the sheets from the first to the last sheet of the set or job.
An example of inversion is seen in U.S. patent application Ser. No. 356,656, filed Jul. 19, 1999, co-owned herewith and to which reference may be had. In this apparatus the first sheet fed thereto is stopped at a staging station at which the second fed sheet is positioned beneath the first fed sheet, and then the two sheets are fed together to a receiving station at which the sheets are inverted to first sheet beneath the second and subsequent sheets in order.